Lemon (I used 2)
4-5 oz Pancetta (optional and not in his recipe)
In his words.
Make sure all of your ingredients and cooking utensils are close by. “You have to move really fast, “ says Frank. Position utensils next to each other, so that nothing gets cold.
Set two pots side by side: one for boiling the pasta and another for mixing the pasta with the lemon and butter.
Boil water and add a handful of salt. (Frank prefers the Celtic kind and loves starchy pasta water.) Put in the spaghetti, and let it cook for no more than 9 minutes.
While the pasta cooks, take the empty pot and place it on top of the pasta water so that it heats from the steam. Do the same thing with the pasta bowls to warm them. “The biggest mistake you can make is to serve this spaghetti on a cold plate, ” says Frank. In other words, the plate should feel warm, so that the butter sauce never solidifies.
When the pasta is ready and very al dente, turn off the burner and keep the spaghetti in the pot with the water. Ladle a couple cups of boiling pasta water into the empty pot to keep it warm. Then dump the water out. Add another ladle of fresh pasta water into the empty pot to begin your sauce. As Frank says, this is the defining moment– “It’s time to rock n roll!”
In that same pot, squeeze two halved lemons. (You can put a strainer beneath them to catch the seeds.) Use tongs to pull out the dripping spaghetti and place it into the pot with lemon water. Add butter. Move the spaghetti in circles with a wooden spoon, so that it becomes coated with the lemon butter sauce. During this process, the lemon, water and butter will emulsify. “The spaghetti acts like a whisk,” says Frank before describing the process in Italian, “Mantecato benissimo.” Throw the lemons in with the spaghetti, so the skins zest the pasta.
Plate the spaghetti with tongs. Pour a bit more lemon butter sauce on top and blanket with parmigiano reggiano cheese. Place the squeezed lemon half on the side for garnish.
I cooked the pancetta until it was crispy before I started the process and set it aside. I topped the spghetti with it because I like that extra salty crunch. I also topped it with red chili flakes for a bit of heat.